A culture microscope is an example of a device for observing a cell. A culture microscope is provided with a culture device for forming an environment suitable for culturing a cell, and a microscope viewing system for microscopic viewing of a cell in a culture container, and the culture microscope is configured so that changes, divisions, and other cell activities can be observed while the living cell is cultured (see Japanese Laid-open Patent Publication No. 2004-229619 for example). In a conventional cell viewing method using such a culture microscope, the state of life or death, degree of activity, and other features of the cell under observation are determined by reagent determination, template matching, or visual observation.